Commercial aluminum alloys, such as the 6063 aluminum (Al) alloy, have been used for fabricating enclosures for electronic devices. However, the 6063 aluminum alloy has relatively low yield strength, for example, about 214 MPa, which may dent easily when used as an enclosure for electronic devices. It may be desirable to produce alloys with high yield strength such that the alloys do not dent easily. The electronic devices may include mobile phones, tablet computers, notebook computers, instrument windows, appliance screens, and the like.
Many commercial 7000 series aluminum alloys have been developed for aerospace applications. Generally, 7000 series aluminum alloys have high yield strengths. However, commercial 7000 series aluminum alloys are not cosmetically appealing when used to make enclosures for electronic devices. For example, commercial 7000 aluminum alloys normally contain zirconium (Zr) and copper (Cu) to strengthen the alloys. Although Cu strengthens the alloys, the Cu-containing aluminum alloys normally exhibit yellowish color after being anodized. The yellowish color is not cosmetically appealing. FIG. 1 depicts an image of an alloy fabricated with a commercial aluminum alloy containing Cu. The color of the alloy is yellowish.
Cosmetic appeal is very important for enclosures for electronic devices. The high yield strength is also important to help resist denting. The commercial alloys (e.g. 2000, 6000, or 7000 series alloys) do not achieve both high yield strength and cosmetic appeal, such as a neutral color, after anodizing and blasting.
There still remains a need to develop aluminum alloys with high strength and improved cosmetics.